montgomery



Jan. 4, 1938.

J. A. MONTGOMERY JIG Fil ed April 24, 1956 INVENTOR James A. Movd'qomer ATTORNEYS- Patented Jan. 4, 1938 JIG James A. Montgomery, Birmingham, Ala., as-

signor of one-half to Howard Moss, Birmingham, Ala.

Application .April 24, 1936, Serial No. 76,130

4 Claims. (01. 209-457) This invention relates to coal washing machines, or jigs, particularly to those known to j the trade as Montgomery Jigs, examples of which are described and claimed in Patents Num- 5 bers 998,373 and 1,949,174, issued to James A.

Montgomery. Coal washing machines of this general type embody a hutch over which is located a perforated screen and a plunger reciprocable beneath the screen. The plunger is prol vided with valve controlled openings through which water is admitted above the plunger on its down stroke, to be forced upwardly through the screen on the up stroke. Beneath the plunger, across the lower part of the hutch, is an inclined l partition wall defining a chamber beneath the plunger. The inclined Wall is provided with valve controlled openings, which admit water to the chamber on theupstroke ofth'e plunger and close on the down stroke. A water supply cham- 2 her communicates with the hutch beneath the partition wall.

The action of washers of this type is-consequently that of an ordinary pump. On the up stroke of the plunger, water is forced upwardly through the screen to stratify the coal thereon, while on thedown stroke, water is admitted above the plunger, and there is a settling of the heavier particles of rock and slate on the screen. Wash ers of this type have proved to be highly efficient in the separation of slate from coal, and large numbers have been in commercial usefor many years. i

I have observed, however, in the operation of jigs of this type, as heretofore constructed, that when the plunger is changing its direction of movement, there is a marked strain upon the mechanism. Very heavy shafts and bearings have heretofore been necessary to withstand this strain. Even with hutch walls of heavy construction, they will be seen to move inwardly and outwardly as the plunger moves up and down. This movement finally leads to leaking and the necessity of repairs. Also, at the'change of motion of the plunger, there has heretofore been a marked pounding of the valves in the plunger and the partition walls which involved undue wear and necessitated their frequent renewal.

Accordingly, the objects of my present inven-.

5 tion are to provide a means for overcoming the beforementioned-difficulties; to reduce the power required for the operation of jigs of the type designated; to provide for the design of a jig of this type with lighter, less expensive parts, and

55 thus reduce the cost thereof; and. also to provide a jig having a longer operating life with less necessity for repair and replacement of parts.

I have found that a great amountv of power has heretofore been dissipatedin the operation of these jigs due principally to three factorshfi which are (1) the speed at which the jigs must operate for satisfactory capacity, which is about strokes per minute; (2) overcoming, at each end of the plunger stroke, the inertia of the moving stream of water generated'by the plunger; 21 and (3) the necessary limitations to theratio of the area of opening of the valves in the plunger and partition wall to the total area of theplunger, which is about 1 to 8.

I have discovered that by the provision of a simple cushioning means, the foregoing difficulties may be obviated and a smoother, more economical operation obtained. Briefly, my invention consists in the provision of a chamber adjacent the hutch, which is closed at the top to 2() permit the compression of air therein, and open at the bottom to communicate with the water chamber between the plunger and the partition wall. With this cushioning chamber, as the plunger changes its direction of movement, the 25 inertia of the moving stream of water is utilized to compress air in the upper part of the chamber, Without shock to the mechanism, and the {compressive force of the air in turn aids in accomplishing the return stroke of the plunger. 30

Apparatus embodying features of my invention is illustrated in the accompanying drawing, forming a part of this application, in which- Fig. 1 is a sectional plan view of my improved jig taken along the line I-I of Fig. 2; and 5 Fig. 2 is a vertical section taken along the line IIII of'Fig. 1.

In the drawing only such parts are shown as are necessary to' an understanding of my invention. Other features usually found in jigs of .40 this type are already well known and form no part of my invention.

My improved jig comprises 'a rectangular tank It! containing partition walls II and [2 which, with the outer walls, define a hutch I3 and a.,45 water well M. A perforated screen 16 extends over the upper part of the hutch, which screen .is preferably inclined, as shown, to assist in the travel of coal thereover as it is being washed. Goal to be washed is fed on to the screen through. 50 asuitable feed chute IT at oneend thereof and travels, while it is being washed, toward the other end of the screen, the Washed coal passing out over a weir .l8, while the slate androck, and other refuse, is discharged through a rotary slate gate I9. The slate gate I9 is driven by any suitable means, not shown, which forms no part of my present invention. V

Disposed within the hutch l3 beneath the screen 6 is a reciprocable plunger 2| having a plurality of valves 22 therein which open on the down stroke of the plunger and close on the up stroke thereof to effect upward pulsations of water through the screen l6. 7 The plunger 2| is reciprocated through rods 23 which extend downwardly through wells 24 in the screen l6, and which are connected at their upper ends to a counter shaft 26. V The counter shaft 26 is connected through links 21 to eccentrics 28 which are mounted on a power shaft 29 driven from any suitable source through a gear 3|.

Extending across the bottom'of the hutch I3 is an inclined wall 32 having a plurality ofyalves 33' therein which open on the upstroke of the.

plunger 2| and close on the down stroke thereof. Water for the operation of the jig 'is supplied through the well M which communicates with the hutch wall 32; The partition wall I 2 separates the hutch from the slate boot 34 into which the refuse is discharged and is removed therefrom by means of an elevator 36. At the 0 sists the plunger and smooths out its operation.'

lower end of the partition wall I2 is an opening 35 through which fines passing down through the screen and plunger are swept by the reciprocating action 'of the plunger into the Slate boot 34. This opening is so restricted in size, however, that it does not materially affect the operation of the jig. I

Extending part way across the tank Ill at the upper end of the screen I6 is an air compression chamber 3'! which, as will be seen in Fig. 2, is closed at its upper end and opens into the hutch at its lower end. The air compression chamber extends upwardly a suificient distance to provide a considerable volume for the compression and expansion of air therein as the plunger 2| reciprocates. In order to more clearly illustrate the invention, the chamber 31 is somewhat exaggerated in size in the drawing, but I have found that with a plunger approximately five feet by three feet six inches in total area, a chamber extend.- a

ing approximately two feet across the short dimension of the screen and approximately six inches inside width, provides, sufficient space to cushion the movements of the plunger.

Theoperation'of my improved jig will be apparent from the foregoing description. Upon the up stroke of the plunger 2|, water is forced upwardly through the screen l6 effectingstratification of the coal and slate, while water is admitted to the hutch 3 beneath the plunger 2| by the opening of the valves '33. As the plunger 2| reaches the end of its up stroke'and starts on its down stroke, the inertia of the moving body of water through the valves 33 is absorbed in the with the valves 22 open,'ha s' its excess compressive force absorbed by the air c ushion in the upper part of the chamber 3'1, the air beingcoinpressed by the upflow of water therein. Then, as the plunger 2| starts again on its :up stroke, the air under compression in the chamber 31 as- By the simple provision of the air compression I ment.

therein as the plunger reciprocates.

2,104,090 it. Y.

chamber 31, I have greatly reduced the weight of the power shaft 29 and its bearings, and have reduced the power required to operate a jig of this type to less than one-half of the former require- For example, where it has formerly required a forty horsepower motor to operate the jig, I have secured an improved operation on a similar jig with a fifteen horsepower motor. In addition, the breathing action of the walls of the tank has been entirely eliminated and the valves have a more prolonged life.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited,but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is: r

1. In a jig, the combination of a screen, a reciprocable plunger for. efiecting upward pulsations of water through the screen and having valved controlled openings therein, means defining a hutch in which the plunger reciprocates including a wall having valved controlled openings for admitting water to the hutch; and an air compression chamber communicating with the hutch between the wall and the plunger, said down stroke and open on the up stroke of the plunger to admit water to the hutch, and means defining a chamber extending upwardly above the screenlevel, said chamber being closed at its upper end, and communicating with the hutch below the screen and the plunger.

3. In ajig, the combination of a hutch, a"

,screen. over the hutch, a reciprocable plunger fitting within the hutch beneath the screen, valves in the plunger which open on the down stroke and close on the up stroke thereof, a wall across the hutch beneath the plunger, valves in the wall which open on the up stroke and close on the down stroke, ofithe plunger, and an air compression chamber extending across the hutch on one side and communicating with the hutch beneath the plunger. 7

4. In a jig, the, combination of a hutch, a screen over the hutch, a reciprocable plunger fitting within the hutch beneath the screen,

valves in the' plunger which open on the down stroke and close on the up stroke thereof, a wall across the hutch beneath the plunger, valves in the wallwhich open on the up stroke and close on the down stroke of th e plunger, and a chamber extending across one side of the hutch and.

opening thereinto beneath the plunger, said chamber extending upwardly alongside the hutch and being closed at its upper end to afford a space forthe compression and expansion of air 7 JAMES A. MONTGOMERY; 

